Magnentius became emperor of the west in A.D. 350, controlling Gaul, Britain and Spain. Although he was willing to share the empire with Constantius II and tried to make peace, hostilities broke out within a year. Initially, Magnentius defeated his rival, but eventually Constantius II, with superior cavalry and archers, gained the upper hand. Magnentius committed suicide in A.D. 353, and for the first time in 16 years, the Empire was again united under one ruler.